Explosive composition



Patented Jan. 4, 1944 EXPLOSIVE COMPOSITION Robert W. Lawrence,Wilmington, to Hercules Powder Company,

Del, asxlgnor Wilmington,

Del, a corporation oi Delaware No Drawing. Application June 29, 1940,Serial No. 343,163

9 Claims. (Cl. 52-7) This invention relates to explosive compositionsand to explosive formulations which have a reduced sensitivity toimpact. More particularly, thi invention relates to a method of reducingthe impact sensitivity of nitroglycerin without adversely affecting theexplosives strength.

Nitroglycerin alone and in admixture with the nitroglycols, the nitratedsugars and the like has been widely used as a constituent of explosivecompositions such as the dynamites and gelatine dynamites. Nitroglycerinhas also found applicm tion in the liquid form for oil well shooting.However, a serious disadvantage in its use for these purposes is itsextremely high degree of sensitivity to impact which causes it to bevery dangerous during handling and especially during trucktransportation, loading of bombs, lowering into oil wells, and otheroperations its sensitivity to impact has made its manufacture,compounding, and use extremely hazardous even under favorableconditions, and although the introduction of many safety measures hasimproved the working conditions many accidents occur which cause damageto property and 10s of life.

Due to the high impact sensitivity, nitroglycerin should not betransported in the liquid state, and even in mixture with oxidizingagents and reducing or carbonaceous materials, special precautions arenecessary during transportation. To overcome these hazards it has beensuggested that the nitroglycerin be colloided with a high percentage ofniirocotton. However such an admixture does not lend itself readily tocompound ing into the desired type explosive on.Ithasrurtherbeensnggested byHaleinlLS. 2,004,941, that nitroglycerin beadmixed with nitroethyl as these materials will reduce its sensitivity.considerable quantity of the nitroethy not only reduces-the impactsensitivity. but also makes the mixture insensitive to blasting caps.Purthermoretheremaybeatthesametimea. considerable reduction in theexplosive strength. It may be noted that even dinitroethyhasthelowoxygenbalanceoi-130% audits explosive energy is low.

Itistheobiectotthisinveniiontom-ovidea material which when with nireduces its sensitivity to impact without unfavorably ailecfing itsstrength.

Afurtherobjectofthisinventonistopmvide ni which may be handled withgreater safety.

However, the addition oi any 40 A further object oi this invention is toprovide explosive compositions which have reduced sensitivity to impact.

A further object or this invention is to provide a liquid explosiveadaptable for use in oil well shooting.

A still further object of this invention is to provide explosivecompositions which are not sensitive to impact, but which will detonatewith a commercial blasting cap.

Other objects will be apparent hereinafter.

In general, the objects of this invention have been accomplished bymixing with the nitroglycerin now known to the art various percentagesof nitro. The nitroparamns are insensitive to impact and will not shootunder ordinary confinement when primed with a No. 8 blasting cap, butwill when in admixture with nitrogLvcerin develop approximately the sameexplosive power as an equal weight of the nitroglycerin that itdisplaces. Thus, by admixing nitroparafflnwithnitroglycerinandusingthese admixtures in various explosive compositions, explosiveshave been produced which have a reduced sensitivity to impactbut whichdo not have a decreased explosive power.

More the objects of this inventionwereaccomplisbdbyadmixingonepartoinitrogiycerin with one part ofnitromethane. The admixture produwd had an oxygen balance of -l8% andthe explodve energy of the mixture was equivalent to that of purenitroglycerin The 50-50 mixture of nitroglycerin and nitromethane wasinsensitive to impact but was sensitive to detonation by a commercialblasting cap. By varying the percentage of nitromethzmeaddedtothenitroglycerlmithasbeenfoimdthat about 15% nitromethanemarkedly reduces the sensitivity of the nitroglycerin and that anadditionof over about 50% nitromethane to nitroglycerin reduces thesensitivity of the nitroglycerin toamiintwherenboosterchargeisrequiredtosiredluadiingtheretoaproperamountoinitmlnordertoshowmoreth g gottheadditimofniimpammntonitroglyeerin,

usblelisaivaiinwhichthepropertiesoi'varloua I Hei btoflali oizkg. weightin the U. 8. Bureau oiMinea imp act machine to produce either shots outof trials or 6 lailnres ii trials. First column shows height for 6 shotsand second for-5 failures.

I 8 indicates shot, Findicaies (allure when ilring with leommercialblasting cap, either No. 6 or No. 8 in size.

'In the above table the nitroglycerin which was used did not include anyof the various materials such as nitroglycol or nitrated sugars that aresometimes added to nitroglycerin. However. the mixing of nitroparamnswith nitroglycerin;- containing materials such as the nltroglycols ornitrated sugars etiects a reduction in the sensitlveness similar to thereduction which is efl'ected when the nitroparaflln is added to purenitroglycerin.

A nitroglycerin composition which comprised 42% nitroglycerin, 41%nitroglycol and 17% aucroseoctanitrate was mixed with varying portionsof nitromethane and the oxygen balance and sensitiveness or theadmixture determined. The

results are given in Table 2.

Table 2 mm "N. 0." ig Banaitlvcneas I o 100 -o. 1 s No. 0. so -n.o BNoJcb. so 00 l5.s Fblo.8cap.

Table 3 fig g "N. o." ai- Sensitivanees o 100 +aa s No. a. $0 70 -0. 8 BNo. 6 cap. 40 co -l4.0 e No. a. so so --is. s r m. a cap.

From the foregoing results it will be seen that nitromethane aifects thenitroglycerin alone or in admixture with other of the nitric esters and,

therefore, wherein. this specification and claims is used the termnitroglycerin, it should be understood that by the term, the compound byitself or with addition or partial substitution of any of the commonlyused freezing point depressants such as, for example, ethylene glycoldinitrate, nitrat ed polymerized glycerin, nitrated sugars, nitratedchlorhydrins and the like is contemplated. The

asseneo term nitroglycerin as here described is well known and acceptedin the art. It has also been found that the nitrobaramns will reduce thesensitiveness of the above mentioned nitric esters when they are usedalone.

It will be observed that sensitiveness of the hitroglycerin as shown inthe abov tables has been materially decreased by the addition of aslittle as 16% of nitromethane. and that by the time the percentage ofnltromethane has been raised to about 80%, the mixture has become quiteinsensitive to impact; and, that on further raising of the percentage ofnitromethane, the admixture becomes less sensitive until it will nolonser detonate with a No. 8 blasting cap. Detonation of the insensitivecomposition may be effected by boosters; e. g., such as a half stick of40% dynamite, or a charge of TNT or tetryl. The use of such boosters isoftentimes desirable and is to be understood as contemplated by thisinvention.

In addition to the reduction of sensitivity which is effected by theaddition of nitromethane to the nitroglycerin, the nitromethane also,due to its low molecular weight and its low freezing point, efle'ctlvelylowers the freezing point of nitroglycerin. Since the nitromethane addedto the nitroglycerin lowers the freezing point, it is unnecessary toinclude with the nitroglycerin high percentages of freezing pointdepressants such as, nitrated glycols and nitrated sugars. This isadvantageous since nitration of the mixtures may sometimes presentdiiilculties not experienced when nitrating glycerin alone.

The liquid explosives comprising mixtures of nitroglycerin andnltromethane in accordance with this invention are highly desirable inoil well shooting. Thus, for example, a mixture of nitroglycerin andnitromethane, 15-25, is very much safer to handle in the liquid statethan pure nitroglycerin and actually provides a means of using a highexplosive composition safely. The use of mixtures 01 nitroglycerincontaining as much as 50% nitromethane for shooting oil wells has beenfound advantageous by the inclusion of a booster charge of TNT ortetryl. The handling and loading of the 50-430 mixture of nitroglycerinand nitromethane even with the inclusion of the booster charge isrelatively safe because the assembly is not sensitive to impact.

The sensitivity of various explosive compositions containingnitroglycerin, oxidizing salts and carbonaceous materials may be reducedby the addition of nitromethane to the composition either by adding itto the nitroglycerin before the nitroglycerin is compounded with theother ingredients or by adding it to the explosive composition after themixing procedure is under way.

Thus the nitroparailin may be added to the explosive composition at anytime during the preparation thereof, or tcthe individual ingredients.Any of the various explosive compositions now containing nitroglycerinmay be reduced in sensitivity by the addition 01 nitromethane withoutreducing their explosiv power and by this addition increased safety isobtained in the compounding. P cking and use of the various explosives.The hazard of handling the explosives is materially reduced and inparticular the hazard accompanying the packing of ordinary nitroglycerinexplosives into cartridges manufactured of paper, plastics or metal issubstantially decreased.

To show the various type explosives which may be compounded by the useof nitromethane, Table 4 is given which lists a dynamite, an ammoniumnitrate dynamite, a gelatin dynamite, and an extra gelatin dynamitecomposition that includes as an ingredient nitromethane:

Table 4 A ll i l) Dymb Ammonium Gelatin tgm' mile "vi gelatin ymmu an edynamite Nitroglyccrin 20 I 25. 0 2n. n Nltl'omlthamil 20 5 25. 0 l0. 0Nitrocellulose 2.0 11,.- Sodiu m lllirnli 4s 23 R0. 0 1&2. n Ammoniumniirate... m 'ZILO Mnnioc meal 7 Wood flour. T 4.0 1.0 asseh 4 4.0 1.0Starch... l. 7.5 Suliur.... 4 Ln (-hnlk. l l Lo Lo I00. 0 100. 0 HXLU100.0

From the above table, it is obvious that the nitromethane of thisinvention may be compound ed with most 01' the various explosivecompositions now known to the art. The addition or nitromethane to theseexplosive compositions, materiaily decreases the sensitivity of thecomposition. The advantage of this invention lies in the fact that thesensitivity of various explosive compositions may be reduced without thereduction of their explosive power.

While throughout the foregoing examples I have used nitromethane, I havealso found that other nitroparaflins such as, for example,dinitroethane, dinitropropane may be substituted for the nitromethane ormay be admixed therewith in order to obtain the decreased sensitivitydesired. The nitroparafllns with materially lower oxygen balances, suchas, nitroethane, nitropropane, and nitrobutane may also be used providedthey are mixed with nitromethane to give a mixture with an oxygenbalance greater than about 100%.

It will be understood that the details and examples hereinbeiore setforth are illustrative only. and that the invention as broadly describedand claimed is in no way limited thereby.

What I claim and desired to protect by Letters Patent is:

1. A dynamite including an oxidizing salt, a carbonaceous material, andan explosive ingredient, said ingredient comprising an admixture of aliquid explosive nitric ester and at least 15% by weight of anitroparafiin composition selected from the group consisting ofnitromethane, dlnitroethane, dinitropropane. mixture of nitroethane andnitromethane, mixture of nitropropane and nitromethane, and mixture ofnitrobuteas and nitromethane. said dynamite being characterized by amuch lower sensitivity to shock than a corresponding dynamite in whichthe nitroparaflin has been replaced by an equal weight of explosivenitric ester.

2. A dynamite including an oxidizing salt, a carbonaceous material, andan explosive ingredlent, said ingredient comprising an admixture of aliquid explosive nitric ester and at least 15% by weight 01' anitroparamn composition selected from the group consisting ofnitromethane. dinitroethane, dinitropropane, mixture oi nitmethane anduitroaiethaue, mixture 01' ultrourm pane and nitromethane, and mixtureof nitrobutane and nitromethane, said dynamite being characterized bybeing insensitive to a blow from a 2 kg. weight dropped from a height'of at least 15 cm. when tested on the U. 8. Bureau of Mines impactmachine.

3. A dynamite including an oxidizing salt, a carbonaceous material, andan explosive ingredient, said ingredient comprising an admixture of aliquid explosive nitric ester and at least 15% by weight ofnitromethane, said dynamite being characterized by being insensitive toa blow from a 2 kg. weight dropped from a height of at least 15 cm. whentested on the U. S. Bureau of Mines impact machine.

4. A dynamite including an oxidizing salt, a carbonaceousmaterial, andan explosive ingredient, said ingredient comprising an admixture oi aliquid explosive nitric ester and at least 15% by weight ofdinitroethane, said dynamite being characterized by being insensitive toa blow from a 2 kg. weight dropped from a height oi at least 15 cm. whentested on the U. S. Bureau of Mines impact machine.

5. A dynamite including an oxidizing salt, a carbonaceous material, andan explosive ingredient, said ingredient comprising an admixture of aliquid explosive nitric ester and at least 15% by weight ofdinitrcpropane, said dynamite being characterized by being insensitiveto a blow from a 2 kg. weight dropped from a height of at least 15 cm.when tested on the U. S. Bureau of Mines impact machine.

6. A dynamite including an oxidizing salt, a

carbonaceous material, and an explosive ingredient, said ingredientcomprising an admixture of nitroglycerin and at least 15% by weight oimtrometnane, said dynamite being characterized by being insensitive to ablow irom a 2 kg. weight dropped from a height of at least 15 cm. whentested on the U. S. Bureau of Mines impact machine.

I. A gelatin dynamite including an oxidizing salt, a. carbonaceousmaterial, and an explosive ingredient, said ingredient comprising anadmixture of nitroglycerin, nitrocellulose and at least 15% by weight ofnitromethane, said gelatin dynamite being characterized by beinginsensitive to a blow from a 2 kg. weight dropped from a height of atleast 15 cm. when tested on the U. 8. Bureau or Mines impact machine.

8. A dynamite including an oxidizing salt, a carbonaceous material, andan explosive ingredient, said ingredient comprising an admixture oimtroglycerin and at least 15% by weight of dinitroethane, said dynamitebeing characterized by being insensitive to a blow from a 2 kg. weightdropped from a height of at least 15 cm. when tested on the U. S. Bureauof Mines impact machine.

9. A dynamite including an oxidizing salt, a carbonaceous material, andan explosive ingredient, said ingredient comprising an admixture ofnitroglycerin and at least 15% by weight of dlnitropropane, saiddynamite being characterized by being insensitive to a blow from a 2kg.- weight dropped from a height 01 at least 15 cm. when tested on theU. S. Bureau of Mines impact machine.

ROBERT W. LAWRENCE.

